Loss of magnetic art fluid after a period of operation is one of the unresolved and very significant problems with conventional magnetic fluid devices, such as for example, magnetic fluid centrifugal seals of the type described in U.S. Pat. No. 4,304,411, issued Dec. 8, 1981 for a "Magnetic/Centrifugal Seal" in the name of Donald F. Wilcock and Martin W. Eusepi, which patent is assigned to Mechanical Technology Incorporated of Latham, N.Y. Replacement of lost fluid after a period of operating life, presents a substantial problem with such devices. Such loss of fluid may be due to evaporation, oxidation, or from just being "blown-out" as a result of a high pressure transient which exceeds the sealing or bearing load capacity of the device, or some similar phenomenon. This is a problem common to all known current designs of magnetic fluid bearings and seals.
The present invention overcomes this prior art problem and shortcoming of magnetic fluid bearings and seals in a very simple and reliable manner by providing a means for automatically controlling and maintaining the supply of magnetic fluid to the magnetic fluid feed area of the magnetic fluid bearing or seal. This system can be utilized to initially fill the magnetic fluid bearing or seal with magnetic fluid, as well as to automatically replace the magnetic fluid which has been lost during operation.